Centrifugal separator



Oct. 18, 1966 J, VON QT L 3,279,611

CENTRIFUGAL' SEPARAI'OR Filed Sept. 15, 1964 4 Sheets-Sheet 1 INVENTOR/I4'M m y MW A W r 4 Sheets-Sheet 2 Filed Sept. 15, 1964 III INVENTOROct. 18,1966 ON RQTEL v 3,279,611

CENTRIFUGAL SEPARATOR Filed Sept. 15, 1964 4 Sheets-Sheet 3 FIG.3 22 J,4

INVENTOR I Oct. 18, 1966 J. VON ROTEL CENTRIFUGAL SEPARATOR 4Sheets-Sheet 4 Filed Sept. 15, 1964 INVENTOF? United States Patent3,279,611 CENTRIFUGAL SEPARATOR Julius von Riitel, Kirschbaumweg 118,Dortmund, Germany Filed Sept. 15, 1964, Ser. No. 396,538 Claimspriority, application Germany, Sept. 17, 1963, R 36,131 17 Claims. (Cl.210-330) The present invention relates to a centrifugal separator, andmore particularly to a centrifugal separator for separating the sol-idcrystalline fraction and the liquid fraction of sugar syrup.

Centrifugal separators serving this purpose are provided with screensthrough which the liquid fraction passes during the separation. Anincrease of the output of the separator can only be obtained byincreasing the size and area of the screen. The area of the screencannot be increased beyond a certain limit by increasing the diameter ofthe separator, since the resulting higher peripheral speed causes agreater centrifugal force, and greater stress on the material of whichthe screens and the separator drum are made. Due to this fact, sugarrefining plants have to use a great number of centrifugal separators oflimited diameter.

It is one object of the present invention to increase the effectivescreen area of a centrifugal separator without increasing the diameterof the rotor of the machine.

In the known centrifugal separator, a plurality of separator pockets arelocated between two circular end walls of a rotary drum. The separatorpockets are not coaxial, and are attached by bolts to the end walls ofthe rotary drum so as to resist the outward action of the centrifugalforce. In order to secure the walls of the separator pockets to thedrum, reinforcing ribs must be provided on the separator pockets so thatthe circumferential extension of the separator pockets is increasedwhereby the number of separator pockets which can be positioned in adrum of limited diameter, is also limited.

A mathematical analysis of the centrifugal forces acting on the bolts ofthe prior art has proven that, assuming an economical minimum width ofthe screens in axial direction, for example about 200 mm., the bolts aresubjected to a substantial bending stress which requires an increase ofthe bolt cross section and the use of hollow bolts requiring even morespace which again results in an increase of the width of the separatorpockets.

It is another object of the invention to mount separator means includingscreens in a rotary drum in such a manner that they abut each other andthe peripheral wall of the drum only under the action of the centrifugalforce.

Another object of the present invention is to provide a centrifugalseparator with a plurality of separator means which are not secured bybolts or other attaching means to the separator drum.

Another object of the invention is to provide such an arrangement ofseparator means that a greater number of separator means includingscreens can be mounted in a drum having a certain diameter than in theconstructions of the prior art.

Another object of the invention is to increase the output of thecentrifugal separator having a given diameter as compared with the priorart constructions.

Another object of the invention is to utilize the increased etiiciencyof a separator having a given relatively small diameter by providingscreens having extremely fine perforations permitting the elimination ofvery fine solid crystalline particles.

In accordance with the present invention a plurality of separator meansare located within a rotary drum in 3,279,611 Patented Oct. 18, 1966"ice circumferentially adjacent positions and have outer ends abuttingthe peripheral wall of the drum and inner ends arranged in a circle.Each separator means includes a separator member forming a cavity and ascreen closing the cavity. The screens and separator members arepreferably curved and extend at angles to radial and tangentialdirections in relation to the axis of the drum. The inner ends of theseparator means form an inner space in the drum into which the substanceto be separated into a liquid fraction and solid fraction is supplied bystationary supply means, such as a pipe having a slot.

Since the minimum width of the separator means is determined by thedimensions of the separator, the diameter and circumferential extensionof the inner space determines the number of separator means which can bemounted in a drum, considering that each inner end of each separatormeans has a certain circumferential minimum extension. The mostfavorable ratio between the diameter of the peripheral wall of the drumand of the circle along which the outer ends of the separator means arelocated, and the diameter of the circle along which the inner ends ofthe separator means are located is 2 to l.

A particular problem is the uniform distribution of the substance to betreated over the circular inner surface formed by the inner ends of theseparator means.

It is known that in separators employing separator pockets the suppliedsubstance is very suddenly accelerated from zero speed to the peripheralspeed. In order to prevent damage to the crystalline solid fraction, itis not only desirable that the substance is accelerated to acircumferential speed corresponding to the circumferential speed of theinner ends of the separator means before the substance enters betweenthe separator means, but it is also necessary that the suppliedsubstance is uniformly distributed over the entire circumference of theinner ends of the separator means, and also over the axial extension ofthe same.

It is another object of the invention to overcome these difficulties,and to supply the substance to the central space within the inner endsof the separator means by a pipe having an axial slot extending over theentire axial length of the separator means. A related object of theinvention is to cover the inner end face of each separator means by aninner projecting portion or tongue of the separator means leading in thedirection of rotation in such a manner as to form an inlet slit.

In this construction of the present invention, the substance which isoutwardly thrown through the slot in the supply pipe cannot directlyenter into the cavities between adjacent separator means, but firstimpinges the end faces of the inner end portions of the separator meanson which they are gradually accelerated and guided toward the screens ofthe separator means.

While this at first results in a delay of the flow of the substance, thecontinuously supplied substance impinges on the substance accumulated onthe end faces so that a ring consisting of the substance is formed onthe inner ends of a separator means which rotates with the same. Thesuccessively supplied substance is taken up by this ring and graduallyaccelerated while the substance enters the inlets between the separatormeans in a continuous flow at the peripheral speed of the inner endfaces of the separator means and passes at such speed to the screens. Inthis manner, the cavities between separator means are closed by theaccumulated substance so that no air can enter into the separator meansand the fan elfect pro- (122532 by the separator means of the prior artis eliminated. The power required for driving the centrifugal separatoraccording to the present invention is substantially reduced since aconsiderable percentage of the sup- 3 plied power may be consumed bymoving air unnecessarily.

The gradual acceleration of the substance to the circumferential speedof the inner ends of the separator means is further improved by theprovision of a plurality of guide vanes curved in accordance with alogarithmic spiral and rotating at a speed lower than the rotary speedof the drum and the separators. The guide vanes have inner ends closelyspaced from the supply pipe and outer ends closely spaced from the innerends of the separator means, and While the substance passes from theinner ends to the outer ends of the guide vanes, it is accelerated untilthe circumferential component of the substance substantially correspondsto the circumferential speed of the inner ends of the separator means.The circumferentially spaced guide vanes alsoeffect the division of thesupplied substance into several streams and a uniform distribution ofthe substance over the inner ends of the separator means.

The inner end portions of the guide vanes are preferably curved in adirection opposite to the logarithmic curvature of the main portions ofthe guide vanes so that the gaps between the inner end of adjacent guidevanes can be reduced to a minimum whereby lumps of solid materialpresent in the supplied substance are retained, and damage to the finescreens of the separator means is prevented.

Adjusting means in the form of a slotted tubular member surrounding theend portion of the supply pipe and the slot therein are advantageouslyprovided for adjusting the amount of substance passing from the supplypipe into the inner central space in which the guide vanes are located.Particularly, when the separation of sugar syrup into a liquid fractionand a solid fraction is intended, a high percentage of particles ispresent which are so fine as to pass through the perforations of thescreens. In order to separate such smallest solid particles togetherwith larger particles, in accordance with the present invention, theangle of curvature of the screens and separator means is selected insuch ,a manner that the component of the centrifugal force causing thetransportation of the substance is smaller than the angle of friction ofthe solid fraction of the substance. Furthermore, rotary oscillationsare produced in the rotary parts of the centrifugal separator whichpreferably are somewhat below the self-frequency of the rotary parts.The rotary oscillations 'are advantageously produced by electromagneticmeans which are energized by currency pulses at the desired frequency ofthe oscillation.

Due to the self-locking effect of the angle of curvature of the screens,the larger solid particles, which have a greater mass, are deposited onthe screens during the operation of the machine, and form a filteringlayer which retains the finer particles and prevents passage of the samethrough the screens. The thus-retained larger and smaller particleswhich together form the solid fraction, are continuously and withoutrelative displacement transported in a continuous manner out of themachine by the effect of the rotary oscillations to which the rotarysystem of the centrifugal separator is subjected.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing, inwhich:

FIG. 1 is a vertical axial sectional view illustrating one embodiment ofa separator according to the invention;

FIG. 2 is a cross sectional view on anenlarged scale taken on line 11-11in FIG. 1;

FIG. 3 is a fragmentary axial sectional view taken on line IIIIII inFIG. 2;

FIG. 4 is a fragmentary sectional view taken on line 1V-IV in FIG. 5;

FIG. 5 is a fragmentary cross sectional view illustrating a detail ofFIG. 2 on an enlarged scale; and

FIG. 6 is a fragmentary sectional view taken on line VIVI in FIG. 5.

Referring now to the drawings, and more particularly to FIG. 1, a motor41 has a shaft 42 carrying a pulley 43 having two pulley portions ofdifferent diameters re spectively connected by V-belts to pulleys 48 and45 which are respectively secured to a shaft 37 and to a hollow shaft 2surrounding shaft 37 and being mounted in bearings 2a of a support 50.The hollow shaft 2 carries a fixed flange 1 secured by screws, notshown, to a circular lateral wall 3 of a rotary drum 51 which includesanother circular lateral wall 7 and a peripheral annular wall4 ofcylindrical configuration around which annular ribs 5 extend. A circularflange 6 is penetrated by screws 9, schematically indicated by dash anddot lines, which hold the lateral wall 7 attached to the peripheral wall4..

Lateral wall 7 has a central opening 8 concentric with the axis of shaft2 and of the rotary drum 51.

Within the rotary drum 51, a plurality of separator means generallyindicated by reference numeral 52. The general arrangement of theseparator means 52 is best seen in FIG. 2, and two adjacent separatormeans 52 are shown in FIGS. 4 and 5.

Each separator means includes a curved wall whose curvature correspondsto a logarithmic spiral whose curvature extends at angles to radial andtangential directions with respect to the axis of the rotary drum. The.in-

wardly facing side of each separator wall 10 is eoncave and formed withgrooves or channels 11 separated from each other by ridges 10a, as bestseen in FIG. 4. The outwardly facing convex side of each separator wall10 is provided at the axially spaced edges thereof with ridges 10b whichhave outer edges curved at the same curvature as walls 10, but whosecircumferential height increases from the inner ends of the separatorwalls toward the outer ends of the same, as best seen in FIGS..

broken line has axially spaced edges resting on corresponding shouldersprovided along the axially spaced edges of wall 10, as best seen in FIG.4. The inner end of each screen 16 is formed as a hollow bead insertedinto the recess of the thicker portion 12, and held in the same byinserted cylindrical plug 19. The outer end of each screen 16 may have abar 16a secured thereto and abutting an abutment portion 20 provided atthe outer end of each wall 10.

Due to the fact that each curved ridge 10b abuts the adjacent wall 10 ofthe adjacent separator means, the abutment portions 20 of the adjacentseparator means are spaced from each other and define between each otheran outlet 23. Outlets 23 are spaced from each other in circumferentialdirection, as best seen in FIG. 2,

and circumferentially spaced outlet openings in peripheral wall 4register, respectively, with outlets 23.

Between each pair of adjacent separator. means 52,. a first cavity 54 isformed which has at the inner end.

drum, as best seen in FIG. 3, and has an outwardly located endterminating in a tubular Outlet means 22.

As best seen in FIG. 4 curved sealing members 40 are provided in the[first cavities 54 adjacent the ridges b to seal the cavities ofadjacent separator means from each other. Sealing members 40 slightlyproject beyond the ridges 1%, as shown in FIG. 4 and abut correspondingshoulders on the adjacent wall 10.

As best seen in FIG. 3 the annular reinforcing ribs 5 which surround theperipheral annular cylindrical wall 4 cross the outlet openings or slots24 in wall 4. In the regions of slots 24, the inner annular edges of theannular ridges 5 are inwardly tapered to form a blade-like edge 5a. Theseparator means 52 are completely identical, and may be manufactured byan injection molding process with exception of the screens 16 which arelater attached. The complete set of separating means 52 is assembled toform a complete ring as shown in FIG. 2 and are clamped together in apackage by clamping means engaging only the axial end portions ofabutments 20. The inwardly directed pressure of the clamping meanscompresses the sealing members 40.

The clamped package of separator means is inserted into the interior ofthe drum formed by walls 3 and 4 after wall 7 has been removed. When theclamping device interferes with further axial insertion, it is removed,and the package of separator means fully inserted, whereupon wall 7 isattached by screws 9 to flanges 6 of the drum 51.

In the embodiment illustrated in FIG. 2, eighty separator means areprovided. Each separator means abuts against the adjacent separatormeans in circumferential direction, and abuts the inner surface of theperipheral wall 4 with abutment portion 20, and more particularly withthe outer abutment face of abutment portion 20 which has a cylindricalshape corresponding to the cylindrical inner surface of wall 4. Theabutment between adjacent separator means takes place along the outercurved convex edges of ridges 10b and the corresponding curved edges ofwall 10 of the adjacent separator means, as best seen in FIG. 4. Tongues14 are held by the inner ends of ridges 10b in such a spacedrelationship as to form very narrow inlet gaps 15 betwen each other.When the package of separator means is inserted into drum 51, theangular position must be carefully chosen so that the outlet slots 23between adjacent abutment portions register with the outlet slots 24 inthe peripheral wall 4 of the drum. After insertion of the package ofseparator means, screws 9 are not fully tightened, and in thiscondition, the drum is rotated so that the centrifugal forces acting onseparator means urges the same outwardly and into abutting engagementwith each other and with peripheral wall 4. When the separator meanstightly abut each other, screws 9 are tightened so that the axialpressure exerted by wall 7 on ridges 10b provides sufiicient friction toprevent any relative turning movement between the package of abuttingseparator means and drum 51.

As best seen in FIG. 2, the inner ends of the separator means, and moreparticularly the tongues 14 which are located along a circle founding acentral inner space 26 within the drum. The outer diameter of the innerspace 26 is approximately one-half of the diameter of the peripheralannular wall 4 of drum 51. Assuming a certain circumferential extensionof the inner ends of the separator means, and the smallest desired widthof the inlet gaps 15, the diameter of the central inner space 26 isgiven. The surface of the screens should be as great as possible. In onepreferred embodiment of the invention, the diameter of the peripheralannular wall is about 1,000 mm., and the diameter of the inner space 26between 450 and 500 mm.

The substance to be separated into a liquid and solid fraction issupplied by pipe 25, and more particularly through an axial slot aleading into the inner space 26.

The circumferential speed of the inner end portions 14 is substantial,and if the substance were directly dropped from slot 25a onto thetongues 14, the crystals of the solid fraction may be damaged when thesubstance is accelerated from the zero speed prevailing in slot 25a tothe circumferential speed prevailing at the inner ends of the separatormeans. In order to gradually accelerate the substance, and also touniformly distribute the substance to all the inlet gaps 15 at the innerends of the separator means, the present invention provides guide vanes33 Within the inner space 26. Each guide vane is formed in accordancewith a logarithmic spiral having an inclination of about 12. The guidevanes overlap each other, and are held together by two axially spacedcircular discs 34 and 35 as best seen in FIG. 1. Disc 34 is secured to aflange 36 carried by shaft 37. As explained above, the pulleys on shafts2 and 37 have different diameters so that shaft 2 is driven at thehigher speed, and shaft 37 driven at a lower speed. Consequently, drum51 rotates at a higher speed than the guide vanes 34, a preferred speeddifference being 3%.

The inner end portion of each guide vane 33 is bent in a directionopposite to the direction of curvature of the main portion of therespective guide vanes 33 and extends into the proximity of the adjacentguide vane forming a narrow inlet gap 39 with the same. The width of thegap may be, for example, 3 mm. whereby lumps forming part of thesubstance supplied through pipe 25 and slot 25a having a greaterdimension than 3 mm. are prevented from passing along the guide vanes tothe separator means. Such lumps are retained by the gaps 39, and may beremoved when the separator is stopped. In this manner, damage to thefine screens 16 by large lumps is prevented.

During operation, a substance containing a solid fraction and a liquidfraction is supplied through pipe 25 and passes through slot 25a indownward direction due to the action of gravity, since the guide vanes33 are rotated by shafts 37, the substance impinges successively on theinner portions of all guide vanes 33 and moves along the same due to theaction of the centrifugal force so as to enter through the inlet gaps 39into the spaces between the outer portions of guide vanes 33 by whichthe substance is accelerated until its circumferential speed componentscorresponds substantially to the circumferential speed of the inner endportions or tongues 14 of the separator means 52 which rotate at thesame higher speed as drum 51. The substance moving in outwardlydirection impinges the overlapping tongues 14 which are so positionedthat the substance deposited thereon is further accelerated incircumferential direction and moves outwardly along the same tending topass into inlet gaps 15. At first, an amount of the substance isdeposited in the form of a ring on the overlapping tongues 14 androtates with the separator means 52 and drum 51. As additional substanceis deposited on the ring of deposited material, it is acceleratedgradually while at the same time the corresponding part of the materialforming the deposited ring enters through inlet gaps 15 into the firstcavities 54 formed between adjacent separator means as best seen in FIG.5. The substance is urged by the centrifugal force to press against therespective screen 16 of the adjacent separator means and to move alongthe same in outward direction. During this travel, the liquid fractionis separated from the solid fraction and enters the second cavity 55,traveling along grooves 11 toward the outlet 21, while the solidfraction travels on the other side of screen 16 in cavity 54 and isdischarged through the aligned outlets 23, 24.

As best seen in FIG. 1, the housing of the machine includes a collectorportion 31 surrounding drum 51 so that solid material discharged fromoutlet openings or slots 24 will be received by collector housing 31after having passed the blade-like inner edges of the annular ridges 5which facilitate the outward movement.

The liquid fraction which has passed through a screen 16 in cavity 55moves along the inwardly concave surface of the respective Wall until itreaches the outlets 21 from which it passes into the axial ducts 21a.Due to the action of the centrifugal force, the liquid fraction'movestoward the outwardly located end of the inclined ducts 21a and isdischarged through outlets 22 which are surrounded by' a frusto-conicalguide 27 secured to wall 3 of drum 51 and rotating with the same so thatthe centrifugal force causes movement of the liquid fraction along theinner frusto-conical surface of ring 27 until the liquid passes over thewider annular edge of ring 27 and into the collector housing portion 28of the collector housing 29, the collector portions 28 and 31 beingseparated by walls. An outlet 30 is provided at the bottom of collectorhousing 28 through which the liquid is discharged. The solid partdischarged into collector housing 31 drops through a correspondingopening 31a at the bottom of collector housing 31.

The inner end 25b of the supply pipe 25 may be surrounded by a sleeve,not shown, having an opening which can be aligned with slot 25a. Whenthe sleeve is turned, a circumferential extension of the superimposedslots is reduced so that a smaller amount of the substance is suppliedto the rotating guide vanes 33.

When the angle of curvature of the screen 16 is suitably chosen, thecomponent of the centrifugal force acting to transport the substancealong the screens is smaller than the friction angle of the solidfraction of the substance. If under such circumstances, the rotary drum51 is subjected to rotary oscillations, preferably somewhat below theself-frequency of the rotating parts, even the finest solid particlesare discharged together with larger solid particles. Such rotaryoscillations may be obtained by electromagnetic means excited at thedesired frequency of the oscillations.

It will be understood that each of the elements described above or twoor more together, may also find a useful application in other types ofcentrifugal separators diifering from the types described above.

While the invention has been illustrated and described as embodied in acentrifugal separator provided with a plurality of separator meansabutting each other and enveloping drums due to the action of thecentrifugal force, it is not intended to be limited to the detailsshown, since various modifications and structural changes may be madeWithout departing in any way from the spirit of the present invention.

Without further analysis the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed and desired to be secured by Letters Patent is:

1. A centrifugal separator comprising, in combination, a rotary drumhaving an axis and a peripheral wall having outlet openings; a pluralityof separator members, and a plurality of screen means alternatelydisposed in said drum in circumferentially adjacent positions abuttingeach other and forming alternating first and second cavities betweeneach other, said screen means and separator members having inner endsforming inlets into said first cavities and having outer ends abuttingsaid peripheral wall and forming first and second outlets from saidfirst and second cavities, said screen means extending at angles toradial and tangential directions in relation to said axis; and means forsupplying a substance containing a liquid fraction and a solid fractionto said inlets so that the substance moving outwardly in said firstcavities under the action of the centrifugal force travels along saidscreen means whereby the liquid fraction passes through said screenmeans into said second cavities and out of said outlets from saidfirstcavities, each separator means hav- 7 ing a second cavity with asecond outlet at said outer end, and including a screen mean closingsaid-second cavity and extending at angles to radial and tangentialdireci tions in relation to said axis; and means for supplying asubstance containing a liquid fraction and a solid fraction to saidinlets so that the substance moving outwardly in said first cavitiesunder the action of the. centrifugal force travels along said screenmeans whereby the liquid fraction passes through said screen means intosaid second cavities and out of said second outlets while the solidfraction is discharged from said first outlets and through said outletopenings.

. 3. A centrifugal separator, comprising, in combination, a rotary drumhaving an axis and an annular peripheral Wall formed with outletopenings, and including a plurality of annular ribs surrounding saidannular peripheral wall and crossing said outlet openings, said annularribs having tapered annular edge portions in the regionzof said outletopenings; a plurality of separator means disposed in said drum incircumferentially adjacent positions abutting each other to form firstcavities between each other and having adjacent inner ends forminginletsinto said first cavities and outer ends abutting said peripheralwall and forming between each other first outletsfrom said firstcavities, each separator means having a second cavity with a secondoutlet at said outer end, and including a screen means closing saidsecond cavity and extending at angles to radial and tangentialdirections in relation to said axis; and means for supplying a substancecontaining a liquid fraction and a solid fraction to said inlets so thatthe substance moving outwardly in said first cavities under the actionof the centrifugal force travels along said screen means whereby theliquidfraction passes through said screen means into said secondcavities and out of said second outlets while the solid fraction isdischarged from said first outlets and through said outlet openingswhile said inner tapered annular edges of said ribs guide the solidfraction in said outlet openings between said ribs.

4. A centrifugal separator, comprising, in combination, a rotary drumhaving an axis and anannular peripheral wall formed with outletopenings, and a pair of walls transverse to said axis, one of said wallshaving a central opening; a plurality of separator means disposed insaid drum in circumferentially adjacent positions abutting each other toform first cavities between each other and having adjacent inner ends.forming inlets into said first cavities and outer ends abutting saidperipheral wall and forming between each other first outlets from saidfirst cavities, each separator means having a second cavity with asecond outlet at said outer end, and including a screen means closingsaid second cavity and extending at angles to radial and tangentialdirections in relation to said axis; and means for supplying a substancecontaining a liquid fraction and a solid fraction to said inlets andincluding a supply pipe projecting through said central opening of saiddrum into the interior of the same the action of the centrifugal forcetraveling along said screen means whereby the liquid fraction passesthroughv said screen means into said second cavities and out of saidsecond outlets while the solid fraction is discharged from said firstoutlets and through said outlet openings.

5. A centrifugal separator, comprising, in combination, a rotary drumhaving an axis and an annular peripheral wall formed with outletopenings; a plurality of separator means disposed in said drum incircumferentially adjacent positions abutting each other to form firstcavities between each other and having adjacent inner ends forminginlets into said first cavities and outer ends abutting said peripheralWall and forming between each other first outlets from said firstcavities, said inner ends being arranged in a circle and forming acentral space within said drum, each separator means having a secondcavity with a second outlet at said outer end, and including a screenmeans closing said second cavity and extending at angles to radial andtangential directions in relation to said axis; a plurality of guidevanes of logarithmic configuration located in said central space andhaving closely spaced inner ends and outer ends located adjacent saidinner ends of said separator means; drive means for rotating said guidevanes at a rotary speed different from the rotary speed of said drum;and pipe means projecting into said central space and located inwardlyof said inner ends of said guide vanes surrounded by the same and havinga slot for supplying a substance containing a liquid fraction and asolid fraction to said inlets so that the substance moving outwardly insaid first cavitie under the action of the centrifugal force travelsalong said screen mean whereby the liquid fraction passes through saidscreen means into said second cavities and out of said second outletswhile the solid fraction is discharged from said first outlets andthrough said outlet openings.

6. A centrifugal separator as set forth in claim wherein said inner endsof said guide vanes have end portions curved in a direction opposite tothe logarithmic curvature of said guide vanes and extending into theproximity of adjacent guide vanes so that narrow inlet gaps are formedbetween the inner ends of said guide vanes.

7. A centrifugal separator, comprising, in combination, a rotary drumhaving an axis and an annular peripheral wall formed with outletopenings; a plurality of separator means disposed in said drum incircumferentially adjacent positions abutting each other to form firstcavities between each other and having adjacent inner ends forminginlets into said first cavities and outer ends abutting said peripheralwall and forming between each other first outlets from said firstcavities, each separator means having a second cavity with a secondoutlet at said outer end, and including a curved inwardly concave screenmeans closing said second cavity and extending throughout its curvatureat angles to radial and tangential directions in relation to said axis;and means for supplying a substance containing a liquid fraction and asolid fraction to said inlets so that the substance moving outwardly insaid first cavities under the action of the centrifugal force travelsalong said screen means whereby the liquid fraction passes through saidscreen means into said second cavities and out of said second outletswhile the solid fraction is discharged from said first outlets andthrough said outlet openings, the angles of curvature of said screensbeing selected so that the component of the centrifugal force acting totransport said substance is smaller than the angle of friction of saidsolid fraction on said screen means.

8. A centrifugal separator, comprising, in combination, a rotary drumhaving an axis and an annular peripheral wall formed with outletopenings; a collector housing surrounding said rotary drum; drive meansfor rotating said drum about said axis; a plurality of separator meansdisposed in said drum in circumferentially adjacent positions abuttingeach other to form first cavities between each other and having adjacentinner ends forming inlets into said first cavities and outer endsabutting said peripheral wall and forming between each other firstoutlets from said first cavities, said first cavities registering withsaid outlet openings in said annular peripheral wall, each separatormeans having a second cavity with a second outlet at said outer end,said second outlet including a duct located in an axial plane passingthrough said axis and being inclined at a small angle to the same, eachseparator means including a screen means closing said cavity andextending at angles to radial and tangential directions in relation tosaid axis; and means for supplying a substance containing a liquidfraction and a solid fraction to said inlets so that the substancemoving outwardly in said first cavities under the action of thecentrifugal force travels along said screen means whereby the liquidfraction passes through said screen means into said second cavities andout of said second outlets while the solid fraction is discharged fromsaid first outlets and through said outlet openings.

9. A centrifugal separator as set forth in claim 8, wherein said rotarydrum includes a pair of lateral walls transverse to said axis, one ofsaid lateral walls having a plurality of circumferentially spaced outletmeans communicating, respectively, with the outer ends of said ducts; afrustoconical guide ring secured to said one lateral wall surroundingsaid outlet means for guiding the liquid fraction in outward and axialdirections away from said outlet means; and a second collector housingsurrounding said frustoconical ring and having a main outlet for theliquid fraction.

10. A centrifugal separator as set forth in claim 9, wherein the otherlateral wall of said drum has a central opening 'bounded by an annularedge located inwardly of said inner ends of said separator means;wherein said means for supplying the substance includes a pipeprojecting through said central opening into the interior of said drumand having a slot for discharging the substance; and guide vanes locatedwithin said drum surrounding said pipe and extending into the proximityof said inner ends and inlets of said separator means; and drive meansfor rotating said guide vanes at a different speed than the rotary speedof said drum.

11. A centrifugal separator as set forth in claim 10, wherein said drivemeans of said drum includes a hollow shaft, and said drive means of saidguide vanes includes a shaft located within said hollow shaft; andcomprising a drive motor, and two transmissions having different ratiosand respectively connecting said drive motor with said hollow shaft andwith said shaft within said hollow shaft.

12. A centrifugal separator, comprising, in combination, a rotary drumhaving an axis and an inner annular peripheral wall formed with outletopenings; a plurality of separator means disposed in said drum incircumferentially adjacent positions each separator means including acurved inwardly concave wall having inner and outer ends, said concaveWall being formed on one side with grooves extending between said innerand outer ends, each concave wall having on the other side thereof ribscurved in accordance with the curvature of the adjacent separator means,each separator means including a screen means extending between saidinner and outer ends on said one side and closing said grooves, saidribs abutting said separator means adjacent said other side and formingwith the same a first cavity, and said grooves and screen means forminga second cavity, said inner ends of said walls of said separator meansforming inlets into said first cavity, and said outer ends of said wallsabutting said peripheral wall and forming between each other firstoutlets from said first cavity communicating with said outlet openingsin said annular wall, said outer ends being formed with second outletscommunicating with said second cavities; said screen means being curvedand inwardly concave and extending throughout the curvature thereof atangles to radial and tangential directions in relation to said axis; andmeans for supplying a substance containing a liquid fraction and a solidfraction to said inlets so that the substance moving outwardly in saidfirst cavities under the action of the centrifugal force travels alongsaid screen means whereby the liquid fraction passes through said screenmeans into said second cavities and out of said second outlets while thesolid fractionis discharged from said first outlets and through saidoutlet openings.

13. A centrifugal separator as set forth in claim 12 wherein said wallof each separator has two ribs at the axial ends thereof, and whereinsaid ribs of adjacent separator means abut each other, said ribs havingouter convex abutment edges having the same curvature as the respectivesurface portions of the adjacent separator means engaged thereby.

14. A centrifugal separator as set forth in claim 13 and includingsealing means located in said first cavities adjacent said ribs andrespectively abutting said walls of adjacent separator means to sealsaid cavities.

15. A centrifugal separator as set forth in claim 13 wherein said innerend of each separator wall has an undercut recess; wherein the inner endof each screen means is formed with a hollow bead located in saidrecess; and including a pin in said recess for holding said inner end ofsaid screen means.

16. A centrifugal separator asset forth in claim 13 wherein said innerend of each wall'of each separator means has a tongue inwardlyprojecting in a direction different from the direction of said wall ofeach separator means and forming with the tongue of the adjacentseparator means a gap constituting said inlet, the width of said gapbeing determined by the height of said ribs at the inner ends of saidseparator means.

17. A centrifugal separator as set forth in claim 13 wherein said outerend of said wall of each separator means is an abutment portionextending in axial direction along the axial extension of said annularperipheral wall of said drum, and having an abutment surface abut- :tingthe inner surface of said annular peripheral wall having the samecylindrical curvature, said abutment portions having radial facesconfronting each other. and forming said first outlets from said firstcavities, said radial faces being located on opposite sides of saidoutlet openings in said annular peripheral wall, and wherein said drumincludes annular ribs surrounding said annular peripheral wall andcrossing said first outlets, said annular ribs having blade-likeinwardly tapered edge portions in the region of said first outlets toguide the solid fraction along the sides of said annular ribs.

No references cited.

REUBEN FRIEDMAN, Primary Examiner,

J. DE CESARE, Assistant Examiner.

1. A CENTRIFUGAL SEPARATOR COMPRISING, IN COMBINATION, A ROTARY DRUMHAVING AN AXIS AND A PERIPHERY WALL HAVING OUTLET OPENINGS; A PLURALITYOF SEPARATOR MEMBERS, AND A PLURALITY OF SCREEN ALTERNATELY DISPOSED INSAID DRUM IN CIRCUMFERENTIALLY ADJACENT POSITIONS ABUTTING EACH OTHERAND FORMING ALTERNATING FIRST AND SECOND CAVITIES BETWEEN EACH OTHER,SAID SCREEN MEANS AND SEPARATOR MEMBERS HAVING INNER ENDS FORMING INLETSINTO SAID FIRST CAVITIES AND HAVING INNER ENDS ABUTTING SAID PERIPHERALWALL AND FORMING FIRST AND SECOND OUTLETS FROM SAID FIRST AND SECONDCAVITIES, SAID SCREEN MEANS EXTENDING AT ANGLES TO RADIAL AND TANGENTIALDIRECTIONS IN RELATION TO SAID AXIS; AND MEANS FOR SUPPLYING A SUBSTANCECONTAINING A LIQUID FRACTION AND A SOLID FRACTION TO SAID INLETS SO THATTHE SUBSTANCE MOVING OUTWARDLY IN SAID FIRST CAVITIES UNDER THE ACTIONOF THE CENTRIFUGAL FORCE TRAVEL ALONG SAID SCREEN MEANS WHEREBY THELIQUID FRACTION PASSES THROUGH SAID SCREEN MEANS INTO SAID SECONDCAVITIES AND OUT OF SAID SECOND OUTLETS WHILE THE SOLID FRACTION ISDISCHARGED FROM SAID FIRST OUTLETS AND THROUGH SAID OUTLET OPENINGS.